Cysteine protease is a generic name of proteases which have a cysteine residue in the activity center and catalyze protein degradation thereat. In animal cells, many cysteine proteases are known; for example, cathepsin family, calpain, caspase, etc. Cysteine protease exists in various kinds of cells extensively and plays a basic and essential role in the homeostasis, such as conversion of precursor protein into its active form (processing) and degradation of proteins which have become out of use, etc. Until now, its physiological effects are being vigorously studied, and as the studies progress and characters of the enzymes are revealed, cysteine protease came to be taken as a cause of really various kinds of diseases.
It is revealed that cathepsin S (see J. Immunol., 161, 2731 (1998)), cathepsin L (see J. Exp. Med., 183, 1331 (1996)) and cathepsin F (J. Exp. Med., 191, 1177 (2000)) play a role in processing of major histocompatibility complex class-II in antigen presenting cells which play an important role in the early stage of immune responses.
In an experimental inflammatory response model induced by antigens, a specific inhibitor of cathepsin S showed an inhibitory effect (see J. Clin. Invest., 101, 2351 (1998)). It is also reported that in a leishmania-infected immune response model a cathepsin B inhibitor controlled an immune response and by means of this effect it inhibited the proliferation of protozoans (see J. Immunol., 161, 2120 (1998)). In vitro, a result is given that a calpain inhibitor and a cysteine protease inhibitor E-64 inhibited apoptosis which is induced by stimuli on T cell receptors (see J. Exp. Med., 178, 1693 (1993)). And cathepsin W, which is expressed in CD8 T cells and NK cells specifically, is known to increase its expression by stimuli of IL-2 by 7 times and so it is conceived that it is concerned with immune responses [J. Immunol., 167, 2172 (2001)]. It is also reported that in leukemia patients, gene expression of cathepsin C and cathepsin W increases and cytotoxic T cells are activated [Int. J. Oncol., 22, 33 (2003)]. Therefore, it is conceivable that cysteine protease is much concerned with the progress of immune responses.
It is speculated that caspase or a similar cysteine protease thereto occupies an important position in the mechanism of cell death including apoptosis. Therefore it is expected for a cysteine protease inhibitor to be used as an agent for the prophylaxis and/or treatment of those diseases concerning apoptosis, such as infectious diseases, deterioration or sthenia of immune function and brain function, or tumors etc. Diseases concerning apoptosis include, acquired immune deficiency syndrome (AIDS), AIDS-related complex (ARC), adult T cell leukemia, hairy cell leukemia, spondylopathy, respiratory apparatus disorder, arthritis, virus-related diseases (HIV, HTLV-1 related diseases (uveitis etc.) and hepatitis C etc.), cancer, collagenosis (systemic lupus erythematosus, rheumatoid arthritis, etc.), autoimmune diseases (inflammatory bowel diseases, Sjoegren syndrome, primary biliary cirrhosis, spontaneous thrombocytopenic purpura, autoimmune hemolytic anemia, myasthenia gravis, insulin dependent (type-I) diabetes, etc.), diseases accompanied by thrombocytopenia (osteomyelodysplasia syndrome, periodic thrombocytopenia, aplastic anemia, spontaneous thrombocytopenia, disseminated intravascular coagulation (DIC) etc.), hepatic diseases such as viral hepatitis (C, A, B, F, etc.) or hepatitis medicamentosa and cirrhosis, dementia (Alzheimer's disease, Alzheimer's senile dementia, etc.), cerebrovascular injury, nerve degeneration diseases, adult acute respiratory distress syndrome, infectious diseases, prostate hypertrophy, hysteromyoma, bronchial asthma, arteriosclerosis, all kinds of lusus naturae, nephropathy, senile cataract, chronic fatigue syndrome, myodystrophy, peripheral neuropathy, etc.
Moreover, caspase-1 is concerned with various inflammatory diseases and those diseases caused by immune disorders, by means of interleukin-1β (IL-1β) production. A lot of diseases are shown to be involved with caspase-1; for example, inflammatory bowel diseases such as ulcerative colitis, inflammatory diseases (insulin-dependent (type-I) diabetes, autoimmune thyroid diseases, infectious diseases, rejection of an organ transplant, graft versus host diseases, psoriasis, periodontitis (above, see N. Eng. J. Med., 328, 106 (1993)), pancreatitis (see J. Interferon Cytokine Res., 17, 113 (1997)), hepatitis (see J. Leuko. Biol., 58, 90 (1995)), glomerulonephritis (see Kidney Int., 47, 1303 (1995)), endocarditis (see Infect. Immun., 64, 1638 (1996)), myocarditis (see Br. Hearat J., 72, 561 (1995)), systemic lupus erythematosus (see Br. J. Rheumatol., 34, 107 (1995)), Hashimoto's diseases (see Autoimmunity, 16, 141 (1993)), etc.), autoimmune diseases, etc. Experimentally, it is reported that in liver injury model induced by lipopolysaccharide and D-galactosamine, a caspase-1 inhibitor improved the symptoms, and it is expected that a caspase inhibitor shows an effect in sepsis, ischemic reperfusion and hepatitis gravis.
It is also shown that cysteine protease is concerned with rheumatoid arthritis. IL-1β is shown to be concerned with this disease (see Arthritis Rheum., 39, 1092 (1996)), and in addition, as autoantibody toward calpastatin (endogenous calpain inhibitor) was found in the serum of the patients [Proc. Natl. Acad. Sci. USA, 92, 7267 (1995)], it is thought that increase of calpain activity leads to the cause of diseases. Also, it is also reported that cathepsin B and cathepsin C activity is increased in leukocyte of patients suffering from rheumatoid arthritis [Biol. Chem., 383, 865 (2002)]. It is reported that in experimental arthritis model the production of inflammatory cytokine is suppressed and affection of arthritis completely in cathepsin C knock-out mice, so it is expected that cathepsin C inhibition leads to treatment of rheumatoid arthritis [J. Clin. Invest., 109, 357 (2002)].
It is also known that cysteine protease causes a disease symptom by decomposing various proteins which compose the organism.
It is reported that cathepsin B plays a role in decomposing muscular protein in the chronic phase of sepsis (see J. Clin. Invest., 97, 1610 (1996)), and in decomposing muscular protein in myodystrophy model (see Biochem. J., 288, 643 (1992)). At the same time it is reported that calpain decomposes the myocyte cell proteins of myodystrophy patients (see J. Biol. Chem., 270, 10909 (1995)).
In ischemic reperfusion model, a result is given that calpain causes degeneration of brain tissues by means of degradation of protein kinase C-β (see J. Neurochem., 72, 2556 (1999)) and that a cathepsin B inhibitor inhibits nerve injury (see Eur. J. Neurosci., 10, 1723 (1998)).
In the brain ischemic model, it is known that the degradation of spectrin by calpain causes a damage and its function disorder in the neurocyte (see Brain Res., 790, 1(1998)) and it is reported that an IL-1β receptor antagonist relieved the symptoms (see Brain Res. Bull., 29, 243 (1992)).
In myocardial ischemic model it is confirmed that cathepsin B activity increases in the lesion (see Biochem. Med. Metab. Biol., 45, 6 (1991)).
In the experiment utilizing ischemic liver injury model, it proved that necrosis and apoptosis of hepatocyte were induced by means of protein-decomposing activity of calpain (see Gastroenterology, 116, 168 (1999)).
Otherwise, it is known that calpain causes cornea turbid by means of degradation of crystalline (see Biol. Chem., 268, 137 (1993)) and that in the lesion of contracted gut mucosa model it was confirmed that the activity of cathepsin B, H and L increased (see J. Parenter. Enteral. Nutr., 19, 187 (1995)) and it is shown that cysteine protease is a cause of the diseases resulting from these protein degradation.
It has been revealed that cysteine protease is concerned with systemic disorders of organs and tissues by shock.
It is shown that IL-1β is concerned with septic shock and systemic inflammatory response syndrome (see Igakuno ayumi, 169, 850 (1994)) and besides, it is reported that in endotoxin shock model induced by lipopolysaccharide, a calpain inhibitor prevented circulatory system disorder, disorders of liver and pancreas and acidosis by means of inhibitory effect of activation of nuclear factor κB (see Br. J. Pharmacol., 121, 695 (1997)).
Since it is reported that calpain is concerned with platelet coagulation process and a calpain inhibitor prevented platelet coagulation (see Am. J. Physiol., 259, C862 (1990)), it is conceivable that a cysteine protease inhibitor is useful for the disorder of blood coagulation. From the fact that calpain activity increased in the serum of the patients of purpura (thrombocytopenia) resulting from marrow transplantation, so it is conceivable that calpain is concerned with the actual disease symptoms (see Bone Marrow Transplant., 24, 641 (1999)).
Caspase-1 inhibitor suppressed apoptosis of blood vessel endothelial cells, which is seen in the early phase of purpura (thrombocytopenia) and is thought to be important for the progression of the pathology afterwards (see Am. J. Hematol., 59, 279 (1998)), so it is expected that a cysteine protease inhibitor makes effect on purpura and hemolytic uremic syndrome.
The effect of cysteine protease and its inhibitor is being investigated in the area of cancer and metastasis of cancer. Since the proliferations of pancreas cancer cells (see Cancer Res., 59, 4551 (1999)) and acute myeloid leukemia cells (see Clin. Lab. Haematol., 21, 173 (1999)) were inhibited by a caspase-1 inhibitor or its receptor antagonist, it is expected that caspase-1 activity is essential for the process of proliferation of tumor cells, and that an inhibitor thereof is effective for these cancers. Also, from the facts that cathepsin B activity increased in colon cancer metastasis model (see Clin. Exp. Metastasis, 16, 159 (1998)), that cathepsin L activity increased in urine of bladder cancer patients (see Urology, 59, 308 (2002)), that cathepsin Z expression was recognized in tumor cells (see J. Biol. Chem., 273, 16816 (1998)), that cathepsin K protein expression recognized in human breast cancer cells proved the relationship of cathepsin K and bone metastasis (see Cancer Res., 57, 5386 (1997)), and that a calpain inhibitor suppressed migration of the cells, which implies that calpain inhibition might be able to inhibit metastasis of cancer (see J. Biochem., 272, 32719 (1997)), a cysteine protease inhibitor is expected to exhibit an inhibitory effect on the metastasis of various malignant tumors.
As to AIDS (AIDS, 10, 1349 (1996)) and AIDS-related complex (ARC) (Arch. Immunol. Ther. Exp. (Warsz), 41, 147 (1993)), it is implied that IL-1 is concerned with the progress of symptoms, and so it is conceivable that cysteine protease inhibition leads to an effective therapy of AIDS and its complication.
Some parasites have cysteine protease activity in their bodies. Cysteine protease in the phagosome of malaria protozoan is an essential enzyme for supplying nutrition of the parasites. Its inhibitor show an inhibitory effect of the proliferation of the protozoan (see Blood, 87, 4448 (1996)).
In Alzheimer-type dementia, it is said that adhesion of non-physiological protein called amyloid to brain is deeply involved with nervous function disorders. Cysteine protease has an activity of generating amyloid by decomposing its precursor protein. Clinically, it is shown that cathepsin B possesses a processing activity of amyloid proteins in the brains of Alzheimer-type dementia patients (see Biochem. Biophys. Res. Commun., 177, 377 (1991)). And expressions of cathepsin B protein (see Virchows Arch. A. Pathol. Anat. Histpathol., 423, 185 (1993)), cathepsin S protein (see Am. J. Pathol., 146, 848 (1995)) and calpain protein (see Proc. Natl. Acad. Sci. USA, 90, 2628 (1993)) and increase of caspase-1 activity (see J. Neuropathol. Exp. Neurol., 58, 582 (1999)) were confirmed in the brain lesions. And it is implied that cysteine protease is concerned with the disease symptoms, by the fact that calpain is concerned with the formation of paired helical filaments which accumulate in Alzheimer dementia patients and production of protein kinase C which stabilizes the protein (see J. Neurochem., 66, 1539 (1996)) and by the knowledge that caspase is concerned with neurocyte death by β amyloid protein adhesion (see Exp. Cell Res., 234, 507 (1997)).
As to Huntington's chorea, cathepsin H activity increased in the patient's brain (see J. Neurol. Sci., 131, 65 (1995)), and the ratio of activated form of calpain (see J. Neurosci., 48, 181 (1997)) increased. In Parkinson's disease, the increase of expression of m-calpain was recognized in the mesencephalon in the patients (see Neuroscience, 73, 979 (1996)) and IL-1β protein was expressed in brain (see Neurosci. Let., 202, 17 (1995)). Therefore, it is speculated that cysteine protease is concerned with the genesis and progress of these diseases.
Otherwise, in the central nervous system, spectrin degradation by calpain is found in the process of injury on neurocyte observed in the traumatic brain injury model (see J. Neuropathol. Exp. Neurol., 58, 365 (1999)).
In spinal cord injured model it was recognized that in glia cells calpain messenger RNA increased and its activity increased in the lesion and the possibility was shown that calpain had much to do with the degeneration of myelin and actin (see Brain Res., 816, 375 (1999)). And IL-1β was shown to be concerned with the genesis of multiple sclerosis (see Immunol. Today, 14, 260 (1993)). Therefore, it is conceivable that a cysteine protease inhibitor is hopeful as an agent for the treatment of these nerve-injured diseases.
Normally, cathepsin S and cathepsin K do not exist in human arterial walls, but it was confirmed that they expressed in arteriosclerosis lesion and they had an decomposing activity of alveolus elastica (see J. Clin. Invest., 102, 576 (1998)) and a calpain inhibitor and antisense of m-calpain inhibited the proliferation of human blood vessel smooth muscle cells and it is shown that m-calpain is concerned with the proliferation of smooth muscle (see Arteioscler. Thromb. Vssc. Biol., 18, 493 (1998)), so it is conceivable that a cysteine protease inhibitor is hopeful for the treatment of blood vessel lesion such as arteriosclerosis, restenosis after percutaneous transluminal coronary angioplasty (PTCA) etc. And it is also reported that LDL induces cathepsin H expression in human monocyte and cathepsin H is concerned with LDL transformation and it is implied that LDL is concerned with circulatory disorder (arteriosclerosis) [Arterioscler. Thromb. Vasc. Biol., 27 (2003)].
It is reported that in liver, cathepsin B is activated in the process of injuring hepatocyte by bile acid (see J. Clin. Invest., 103, 137 (1999)) and so it is expected that a cysteine protease inhibitor is useful for cholestatic cirrhosis.
It is reported that in spleen, cathepsin Y is concerned with production of bradykinin potentiating peptide (BPP) which plays some role in converting kinin into bradykinin [Immunopharmacology, 45, 207 (1999)]. Therefore, it is expected that cathepsin Y inhibitor has anti-allergy effect.
In lungs and respiratory system, it is shown that cathepsin S is an enzyme that plays a role in elastin degradation by alveolus macrophages (see J. Biol. Chem., 269, 11530 (1994)), so it is probable that cysteine protease is a cause of pulmonary emphysema. In IL-13 transgenic mice in which COPD-like pathology is recognized, increase of cathepsin B, S, L, H and H expression is recognized and it is also reported that administration of a cysteine protease inhibitor suppresses lung inflammation and lung emphysema [J. Clin. Invest., 106, 1081 (2000)]. And it is also shown that lung injury (see J. Clin. Invest., 97, 963 (1996)), lung fibrosis (see Cytokine, 5, 57 (193)) and bronchial asthma (see J. Immunol., 149, 3078 (1992)) are caused by way of production of IL-1β by caspase-1. It is also shown that blood cathepsin H concentration is increased in asthma patients, so antiasthma effect by its inhibitor is expected [Clin. Chim. Acta, 310, 113 (2001)]. It is known that cathepsin H functions in the excision of surfactant protein C which is synthesized by type-2 pneumonia cells [Am. J. Respir. Cell Mol. Biol., 26, 659 (2002)].
It is pointed out that cysteine protease is also concerned with diseases concerning bones and joints. Cathepsin K is specifically recognized in osteoclast and it has a decomposing activity against bone matrix [J. Biol. Chem., 271, 12517 (1996)], so its inhibitor is expected to show an effect in osteoporosis, arthritis, rheumatoid arthritis, osteoarthritis, hypocalcaemia, osteometastasis of cancer, where pathologic bone resorption is recognized. Also, since IL-1β is shown to be concerned with bone resorption and cartilage degradation, and a caspase-1 inhibitor and IL-1β receptor antagonist inhibit the symptoms of bone resorption and arthritis, so it is expected that it is effective for arthritis (see Cytokine, 8, 377 (1996)) and osteoporosis (see J. Clin. Invest., 93, 1959 (1994)). And it is also reported that IL-1β is concerned with osteoarthritis (see Life Sci., 41, 1187 (1987)).
Cysteine protease is involved with production of various hormones. Since increase of messenger RNA of cathepsin S was recognized by stimuli of thytropin on thyroid epitheliocyte strains (see J. Biol. Chem., 267, 26038 (1992)), it is conceivable that a cysteine protease inhibitor is effective for hyperthyrodism.
Since quantity and activity of cathepsin B protein increased in the gingival sulcus liquid of periodontitis patients [J. Clin. Periodontol., 25, 34 (1998)], it is pointed out that cysteine protease is concerned with periodontitis.
On the other hand, serine proteases include thrombin, chymase, trypsin, chymotripsin, urokinase, plasmin, elastase, etc. Thrombin, which is produced in blood coagulation cascades, decomposed fibrinogen to form fibrin and activates the factor VIII. Thrombin is concerned with thrombophlebitis, thrombosis and asthma.
Pancreatic elastase is concerned with pancreatitis. Chymase is an important enzyme in angiotensin synthesis and it is concerned with hypertension, myocardiac infarction, and coronary heart diseases. Cathepsin G is concerned with abnormal connective tissue decomposition.
Therefore, those compounds which have an inhibitory activity against cysteine proteases, are useful as agents for the prophylaxis and/or treatment of inflammatory diseases (periodontitis, arthritis, inflammatory bowel diseases, infectious diseases, pancreatitis, hepatitis, glomerulonephritis, endocarditis, myocarditis, ulcerative colitis, etc.), immune diseases (diseases induced by immune response disorder (graft versus host diseases, rejection during transplantation, allergic diseases (asthmatic bronchitis, atopic dermatitis, allergic rhinitis, hay fever, diseases by house dust, hypersensitive pneumonia, food allergy, etc.), psoriasis, rheumatoid arthritis, etc.), autoimmune diseases (insulin dependent (type I) diabetes, systemic lupus erythematosus, Hashimoto's diseases, multiple sclerosis, etc.), acquired immune deficiency syndrome (AIDS, AIDS-related complex (ARC), etc.), ischemic diseases (brain ischemia, brain disorder by ischemic reperfusion, cardiac infarction, ischemic liver damage, etc.). respiratory diseases (adult acute respiratory distress syndrome, lung disorder, fibroid lungs, decomposition of alveolus elastica (emphysema etc.), etc.), circulatory diseases (arteriosclerosis, restenosis after PTCA (percutaneous transluminal coronary angioplasty), hyperlipidemia, etc.), blood diseases (thrombocytopenic purpura, hemolytic uremic syndrome, myelodysplastic syndrome, cyclic thrombocytopenia, aplastic anemia, spontaneous thrombocytopenia, disseminated intravascular coagulation (DIC), spontaneous thrombocytopenic purpura, autoimmune hemolytic anemia, hyperlipidemia, etc.), neuronal diseases (dementia such as Alzheimer's disease, Alzheimer-type senile dementia, cerebrovascular injury, peripheral nerve injury, neurodegenerative disease (Huntington's chorea, Parkinson's disease, multiple sclerosis, traumatic encephalopathy, traumatic spondylopathy, etc.), etc.), hepatic or biliary diseases (primary biliary cirrhosis, viral hepatitis (A, B, C, F, etc.) or hepatitis medicamentosa and cirrhosis, etc.), osseous or articular diseases (osteoporosis, rheumatoid arthritis, arthritis, osteoarthritis, hypocalcaemia, osteometastasis of cancer, bone fracture, etc.), metabolic diseases (osteoporosis, rheumatoid arthritis, arthritis, osteoarthritis, hypocalcaemia, bone metastasis of cancer, endocrinesthenia (hyperthyroidism etc.), diseases induced by apoptosis (graft versus host diseases, rejection during transplantation, acquired immunodeficiency syndrome (AIDS), AIDS-related complex (ARC), adult T cell leukemia, hairy cells leukemia, spondylopathy, disorders of respiratory apparatus, arthritis, HIV or HTLV-1 related diseases (uveitis etc.), virus related diseases (hepatitis C etc.), cancer, collagenosis (systemic lupus erythematosus, rheumatoid arthritis, etc.), Sjoegren syndrome, myasthenia gravis, autoimmune diseases (insulin dependent (type I) diabetes, etc.), infectious diseases, prostatomegaly, hysteromyoma, bronchial asthma, nephritis, senile cataract, chronic fatigue syndrome, myodystrophy, etc.), diseases induced by decomposition of proteins which compose a body (myodystrophy, cataract, periodontitis, hepatocyte injury by bile acid (cholestatic cirrhosis etc.), etc., shock (septic shock, systemic inflammatory responsive syndrome, endotoxin shock, acidosis, etc.), malignant tumor, AIDS-related complex, parasitic diseases (malaria etc.).
Further, an elastase inhibitor is useful for the treatment and/or prophylaxis of diseases resulting from hyperactivity of decomposition of elastin, collagen fiber and/or proteoglycan by elastase in mammals, particularly in humans, for example, chronic obstructive pulmonary diseases (COPD) such as decomposition of alveolus elastica (emphysema etc.), rheumatoid arthritis, atherosclerosis, adult respiratory distress syndrome (ARDS), glomerulonephritis, myocardial infarction, ulcerative colitis, parodontitis apicalis, etc.
On the other hand, what is the most important for inhibitors in inhibiting the activity of proteases is, the special reaction site which interacts with the amino acid residues the activity center of proteases. The surrounding structure of the reaction sites are represented by—P3P2P1-P1′P2′P3′—, centering peptide binding (P1-P1′) of the reaction site, and at P1 site there exist amino acid residues which fit the substance specificity of proteases which the inhibitors aim. Some reaction sites against cysteine proteases are known, for example, in the specification of WO99/54317, the followings are described;    P1 position against calpain I, II—norvaline, phenylalanine, etc.    P1 position against calpain I—arginine, lysine, tyrosine, valine, etc.    P1 position against papain—homophenylalanine, arginine, etc.    P1 position against cathepsin B—homophenylalanine, phenylalanine, tyrosine, etc.    P1 position against cathepsin S—valine, norleucine, phenylalanine, etc.    P1 position against cathepsin L—homophenylalanine, lysine, etc.    P1 position against cathepsin K—arginine, homophenylalanine, leucine, etc.    P1 position against caspase—aspartic acid, etc.
The followings are known to possess alpha amino acid-derived diketohydrazine skeletons.
EP1008592 discloses a compound of formula (A)
as cathepsin K inhibitor, wherein the following compound (CAS Reg. No. 274684-59-2)
is disclosed specifically.
WO 99/17775 discloses a quinoline derivative of formula (B)
as cysteine protease and serine protease inhibitor, wherein the following compound (CAS Reg. No. 222959-79-7)
is disclosed.
U.S. Pat. No. 6,242,494 discloses a compound of formula (C)
as methionine aminopeptidase-2 inhibitor.
Croatia Chemica Acta 1978, 51(1), 81-92 discloses that the following compound has anti-inflammatory activity.
